Closed cycle air turbine power plant having direct and indirect heat exchangers



Dec. 16, 1952 A. T. BowDEN I 2,621,481

CLOSED CYCLE AIR TURBINE POWER PLANT HAVING DIRECT AND INDIRECT HEAT EXCHANGERS Filed Aug. l5, 1947 Patented Dec. 16, 1952 CLOSED CYCLE AIR TURBINE POWER PLANT HAVING DIRECT AND INDIRECT HEAT EXCHAN GERS Andrew Thomson Bowden, Newcastle-on-Tyne,

England, assignor to C. Limited, Newcastle-on- Application August 15, 1947, Serial No. 768,728 In Great Britain September 25, 1946 2 Claims.

This invention relates to turbine plants of the kind in which a gaseous working medium after compression in one or more compressors to a pressure above atmospheric pressure is heated by an external source of heat and thereafter expanded in one or more turbines driving the aforesaid compressor or compressors and/or providing a source of useful external energy.

With the direct heating of a working medium diiculties arise because, for example, of its low heat capacity and consequent tendency towards the formation of slag on the heating tubes through which it is circulated when, for example, a fuel such as coal is employed as the source of heat supply.

The Object of the present invention is to provide arrangements whereby these difficulties may be eliminated or reduced to a minimum.

The invention consists in a gas turbine plant of the kind indicated wherein the working medium is heated partly directly by the products of combustion of a solid, liquid or gaseous fuel and partly through the intermediary of an auxiliary uid or fluids which also receive heat from the said products of combustion.

The invention also consists in a gas turbine plant as set forth in the preceding paragraph wherein said auxiliary iiuid has a higher heat capacity than that of said medium.

The invention also consists in gas turbine plants as set forth in either of the two preceding paragraphs wherein the working medium circulates in a closed or open circuit. k:

The invention also consists in gas turbine plants as set forth in any of the three' preceding paragraphs wherein the working medium after passing from the turbine or turbines is led directly or in entirety or in part through a heat exchanger to a cooler preceding the 'compressor inlet.

The invention also consists in a gas turbine plant substantially as hereinbefore described with reference to the accompanying drawing.

The accompanying diagrammatic drawing illustrates one convenient arrangement of gas turbine plant embodying the present invention.

In accordance with the invention by the use of an auxiliary uid or fluids of higher heat capacity than that of the working medium-which auxiliary fluid takes up heat from thelproducts of combustion of the fuel and in turn"l give up such heat to the working medium in a suitable heat exchanger, suicient heat having been extracted from the products of combustion by the intermediary fluid to reduce the temperature conditions of the former to a suitable gure, for

A. Parsons & Company Tyne, England example, the fusion point of the ash, when coal is used as thel source of heat supply-'the said products of combustion may give up additional heat to the working medium by direct contact with the channels through which it is circulating.

In a particular application the working fluid is air, the source of heat supply is coal and the intermediaryy vfluid water, steam, or a mixture of Water and steam.

In carrying the invention into eifect according to one form illustrated by Way of example in the accompanying drawing as applied to a closed circuit arrangement, an air compressor a is provided the air from which is led to a channel h of a heat exchanger c directly by way of pipe o or alternatively in whole or in part through a channel i of a heat exchanger b where it takes up heat from the hotter working medium exhausted from a turbine f. In a heat exchanger c the working medium receives heat from an intermediary fluid, e. g. water, of higher heat capacity than that of air, which is circulated through a. cooperating channel j. The auxiliary uid in turn receives heat from the products of combustion in a, heat exchanger pipe e within a nre-chamber p which is fired by solid, liquid or gaseous fuel as by means of the burner 7c schematically indicated in the drawing. The air is then further heated in the pipe of a heater d by the said products of combustion after these latter have given up heat as aforementioned to the intermediary fluid.

On exit from the pipe d the air passes'by Way of a pipe l to the turbine f and after expansion therein is led in its entirety or in part through a channel m of the heat exchanger b, or alternatively, directly to a pipe n of a cooler g and hence to the inlet of compressor a.

What is claimed is:

1. In a gas turbine plant having a turbine and a compressor for supplying the working medium thereto, a heating system comprising a burner and a fire chamber for receiving combustion products therefrom, a heat exchanger for the indirect heating of the working medium having a channelfor aforesaid Working medium and a cooperatingl .channel for an auxiliary fluid, part of said cooperating channel being situated inside the fire chamber for the heating of the auxiliary iluid which in turn gives up its heat to the working medium, the channel for auxiliary fluid being arranged lforv transferring to the working medium channel substantially all the heat extracted from the re chamber, a further heat exchanger for the direct heating of the working medium situated in the re chamber downstream of the auxiliary fluid channel of the fxrst mentioned heat exchanger, and having channels, around the outside oi which the combustion products flow, giving up their heat to the working medium flowing inside the channels, said WorkingV medium entering the said turbine on leaving this heat exchanger.

2. A gas turbine plant and heating system therein as claimed in claim lfwhereinthe auxiliary fluid has a greater heabcapacitythan the Working medium.

ANDREW THOMSON BQWDEN.

REFERENCES CITED Number UNITED STATES PATENTS Name Date Baumann Oct. 17, 1933 Baumann etal.V Mar. 5, 1935 V Rosencrants July13, 1937 Muir Sept. 20, 1938 Randel June 20, 1939 Loveless Mar. 11, 1941 v.Keller Dec. 30, 1941 ILarrecq Oct. 13, 1942 Nettel Nov. 5, 1946 Ruegg Apr. 22, 1947 .Lysholm June 3, 1947 .Stalker May 17, 1949 

